Liquid core binder



Patented Aug. 6, 1929.

UNITED STATES PATENT OFFICE.

WILLIAM R. IPATE AND JOSEPH A. GITZEN, OF MILWAUKEE, WISCONSIN,ASSIGNORS TO' LINDSAY-MCMILLAN CO5 OF MILWAUKEE, WISCONSIN, ACORPORATION OF WISCONSIN.

LIQUID CORE BINDER.

No Drawing.

are powdered rosin and linseed oil.

The rosin produces what is called a rosin or soft "core and the linseedoil produces what is called an oil or hard core. 7

The core 'is molded from the sand. and

binder mixed together and then it is heated or baked.

The powdered rosin becomes unified and distributed in the sand While thecoreis after the grated by the heat from the molten metal.

Powdered rosin, though constituting a binder forcore sand whichwillbecome plastic when heated to the temperatures involved in corebaking and in the casting of metal,

has certain decided disadvantages. For ex-' ample, rosin is very stickyand hard to main-' tam in a pulverized formp Consequently, particularlyif the room 1s hot, the pulverized rosin will form into lumps which whenmixed with sand by the'core maker produces a nonhon1ogeneous mixture,resulting 111 pockets when the core is baked or when the core issubjected tothe action of themolten metal in a mold lVhenthese pocketsappear on the exterior of the core, the result 1s a rough casting.Another disadvantage of the useof powdered rosin as a binder in-a coreis that the core does not presenttha strength or toughness required inmany v t f ter,1c'ombined in such proportions that the The presentinvention has as its object .to

operations.

. casting.

()l'JJGCt oi: the present invention is to provide Application filedApril 11, 1927. Serial No. 182,998.

provide a liquid corebinder which will be solidified by 'theiheat inbaking the core and which will be softened and disintegrated bv the heatof the molten metal. "I

Another object is to provide a liquid core binder which may be readilyand economically manufactured. a

Another object istoprovide a liquid core binder which Will readilyintermingle with the sand and which Will not cause the core to adhere tothe mold in Which it is formed.

Another object is to' provide a core binder which is convenient in use,which may be readily and u'niformly mixed with the core sand, whichwillhold together the particles of the core sand with sufficienttenacity to permit the cores to be handled, and which will permit thenecessary disintegration of the core after the casting operation iscompleted.

Another object is to provide a liquid core binder which will becomeplastic under the temperatures encountered in the casting of metal,whereby shrinkage or other stresses set up during the cooling operationof the casting will not result inthe production of destructive stressesto produce cracks in the Expressed in other language, an

a core binder which will produce a core which is 1 lastic under thetemperatures encountered in metal casting operations, whereby the corewill give, or yield, as shrinkage occurs in the cooling of the castmetal.

Another object is to provioe an improved core'having the advantages ofplasticity and toughness above referred to.

According tothis invention as it has been employed in practice, theliquid core binder comprises resin or other suitable soluble bindingmatter, petroleum oil or distillate or other volatile solvent, andlinseed oil'or other suitable strengthening or' drying matbindingmatterremains in solution in' the solvent under normal temperature andthe rosin maintains its fumlamental characteristics and constitutes thebasic binder.

The liquid core binder provided by this invention has many advantageouscharacteristics, among which are the rosin is in solution and willreadily and uniformly intermingle with the sand, it will be soliditiedby the heat in baking the core to bind the sand together and hold thecore in shape, and it will become plastic and then disintegra e underthe heat from the molten metal.

The invention will he further understood and explained from the binderwhich is set forth in the following composition:

Rosin 40% Light petroleum oil 28 Beaum gravity 10% P e t r 0 l e u mdistillate 40 mi ht Beaiun gravity 44% Raw linseed oil 5% Pine oil 1%The rosin constitutes the basic binder and it is in solution .in thelight petroleum oil and the petroleum distillate which are a volatilesolvent therefor.

The linseed oil gives the rosin increased strength and tenacity (that iscohesion or toughness) and lessens the rosin required to bind the sandtogether.

'hen 40% rosin and 5% linseed oil are present, the binder will havesubstantially the same strength as 60% rosin alone.

The linseed oil which is employed is insufiieient in amount to impairthe rosin or overcome its characteristics.

Vhen even about 10% linseed oil is present the rosin will still be thebasic binder and maintain its characteristics over the linseed oil.

The pine oil is a ready rosin solvent and promotes maintaining the rosinin solution. The linseed oil, in addition to having dryingcharacteristics to increase the strength and tenacity of the binder,constitutes a solvent. for rosin. Therefore, all of the liquids employedwith the rosin act cumulatively to hold the rosin in solution.

The solvent retains the rosin in permanent solution under ordinarytemperature.

When the core in which the binder is employed is heated and baked, thesolvent is volatilized and eliminated and the rosin and the linseed oiltherein are solidified to bind the sand together. The distillatedistills'out with the water in the core sand at the core bakingtemperatures.

The provision of the petroleum solvents having differentboiling'f'points produces the following'advant'ag'es":The lightpetroleum oil (which for examplemay be paraffin oil) permits the meltingof the rosin without decomposition thereof. Later on in the baking ofthe core, said light petroleum oil protects the rosin, so that if toohigh a temperature should be used. or baking should be com tinned fortoo long a time, the rosin is protected against decomposition. Thelighter distillate has the advantage that the mixture is renderedsufliciently fluid to distribute itself unitormly throughout the coresand.

In order to facilitate making the binder and to lessen thevolatilization thereof under normal.temperature, the light petroleum oiland the petroleum distillate are employed as the solvent.

.The-light petroleum oil is less volatile than the petroleum distillate,and the petroleum distillate is more fluid and less adhesive than thelight petroleum oil.

According to the ordinary process employed to make the binder, the rosinis dissolved under heat which is suliieient to melt the rosin.

\Vhen the solution thus obtained is reduced to substantially normaltemperature, the petroleum distillate is introduced to make it morefluid and to lessen its adhesiveness.

The linseed oil may be introduced either while the solution is heated orafter it is cooled.

The pine oil is introduced after the solution has been cooled.

According to another process for making the hinder, the rosin while itis in a heated liquid state in being obtained from its original sourceis dissolved in the light petroleum oil and then the other ingredientsare incorporated in the way which has been set forth.

An important feature of the present in-,

vention is that it provides the advantages of rosin in that the corewill become plastic under heat (followed by disintegration of the core)as the temperature of the core is raised to a predetermined value. Thepresent invention has the advantage over rosin that, being a liquid,distribution throughout the core sand is more readily and uniformlyaccomplished. The present invention has the further advantage over dryrosin that the flying powder does not have to be contended with.

The present invention has decided advantages over 011 cores (that is,cores comprising sand and core oil or comprising sand and linseed oil,)in that it provides plasticity, whereas oil cores do not haveplasticity. An oihcore will not soften under heat,

went invention ing oil core will, in many instances, produce breakage ofthe casting. Oilcores, however,

by reason of their cheapness, have a field of usefulnessin many types ofcastings Where breakage of the cast ngs is not likely to occur, as forexamp'lewuh gray iron castings,

which have a relatively low shrinkage modulus, or in castings sodesigned that the shrinkage is low. The present invention lies in afield distinct from oll cores and con stitutes an improvement over rosincores.

The present invention is particularly ap plicable to the making ofcastings m which the core shouldchange its shape under the shrinkageofthe casting. Cast ngs are p raetic-ally always pro'vided withapertures which permit the oozingof the plastic core therethrough. Coresmanufactured accord-- the liquid core-binder according. tothe-presplasticity stage.

iii-"many instances, for the reason that the fluidcomprising the presentinvention'jpen mcates the core sand muchmore readily than doespulverized rosin and is decidedly. more eflicientas a binder'than ispulverized ros n.

Therefore, less of the liquid employing the principles of'the presentinvention is required .(by weight) for-a unit amount of sand than isrequired of rosin. q i

Added to this advantage is the advantage that no lumps of rosin willcollect on the surface of the core, which lumps will fall out eitherduring the core baking operation or thereafter; leaving a rough surfacewhich promotes chafing when the cores contact withone another instorage. Expressed in other language, cores made with liquid employingthe principles of the present inven tion are smoother than rosin cores,and consequently will not wear away and crumble A further ad vantage isthe smoother casting 'resultlng as readily as rosin cores.

from the practiceof the present invention.

Still another advantage of the presentin-" vention is the reduction otlabor cost from.

the cost involved in the working of rosin,

inasmuch as the n'lani-pulation otthe core hinder employing theprinciplcslof the present invention doesnot have the unpleasant featuresof flying powdered ros n. 1

Of course, the composition which has been set fOItl1' l1C!0il1 toillustrate the invention and further the process of making the same maybe modified in various ways.

' The invention claimed is as follows:

will disintegrate after the baking temperatures, and

1. A liquid core binder comprising rosin about forty percent a volatilesolvent about fifty-five percent and linseed oil about five percent (5%)by weight.

2. A liquid core. binder comprising rosin about forty percent (40%),petroleum oil about ten percent (10%), petroleum distillate aboutforty-live percent (45%) and linseed oil about five percent (5%) byWeight.

3. A liquid core binder comprising rosin about forty percent (40%),light petroleum oil about ten percent (10%), petroleum distillate aboutforty-four percent (44%), linseed oil about five percent (5%) and pineoil about one percent (1%) by weight.

.4. A core binderadapted for use with core sand in the manufacture ofbaked cores col-uprising a liquid including resin in a suliicient amountto constitute the essence of metal casting temperatures, and a solventHOH VOlELiZIlG: under normal temperatures,

' said rosin being in solution in; said solvent, ing to the presentlnvention oremploying said solvent including petroleum derivatives andlinseed'oil.

I 5. A core binder adapted for use with core sand in the manufacture ofbaked cores comprising a liquid including resin in a suiticicnt amountto constitute the essence of said co re binder and insure plasticity.under metal .CRStInQ temperatures,. and a solvent nonvolahleundernormal- .temperatures, said rosin being in solution in said solvent,said solvent includingpetroleum derivatives and an oil having dryingcharacteristics.

6.: A core resulting from the application of core baking temperature toa mixture of core sand and a binder, which binder is a liquid undernormal 'tei'nperatures and includes resin in a suflicient-quantity tobind the par- 'ticlesof said core into a mass plastic under metalcasting temperatures, said rosin being dissolved in a liquid includingpetroleum. derivatives non-volatile at normal temperatures and linseedoil. i

7. A. core resulting from the application of core baking temperature toa mixture of core sand and a bi nder which binder is a liquid undernormaltemperaturesand ineludes rosin in a suflicient quantity to bindthe partieles of said core into a mass'plastic under metal castingtemperatures said rosin being dissolved in a liquid including petroleumderivatives non-volatile under norvmal f tem eraturesjand an oil havingdrying characteristics.

8. A core resulting from the application of heat-"to a mixture of coresand and a binder, w'hich hinder containssuiiicient' rosin to bind theparticlesot said coresand into a mass plasticunder meta-l castingtemperatures, a solvent for said rosin non-volatile atnormaltemperatures but volatile at core an oil having drying characteristics,said oil being in sufli- 1 inous substance dissolved in a mixture ofpetroleum solvents having difierent boiling points and non-volatileunder normal temperatures and an oil having drying characteristics, saidpetroleum solvents and said oil having cumulative solvent actions onsaid resinous substance, saidoil being insuflicient in quantity toharden said binder beyond a plastic stage at metal casting temperatures.

, In witness whereof we have hereunto subscribed our names.

\VILLIAM R. PATE. JOSEPH A. GITZEN.

